Cisco troubleshooting commands

Display live syslog messages [on/off]

SW1# terminal monitor
SW1# terminal no monitor

Show log

SW1# show logging
SW1# show logging history

Show IP address of each interface

SW1# show ip int br
SW1# show ip interface brief

Show route

SW1# show ip route

Show IP address of vlan 172

SW1# show ip int br vlan 172

Show interface description

SW1# show int desc
SW1# show int desc | inc xyz

Show vlan

SW1# show vlan 
SW1# show vlan brief
SW1# show vlan id 172

Show trunks

SW1# show interfaces trunk

Show etherchannel summary

Switch# show etherchannel summary

Show running configuration

SW1# show running-config

Show error disabled interfaces

SW1# show interfaces status err-disabled

Show which type of errors automatically recovers

SW1# show errdisable recovery

Enable autorecovery for all cause

SW1(config)# errdisable recovery cause all

What is being detected (all by default. Do not change this)

SW1# show errdisable detect

For WAN DHCP interface

duplex auto
speed auto
no shutdown

Troubleshoot poor network (collisions, bandwidth)

R# show platform error
show interfaces switching
show interfaces stats

Find out IP & MAC

R#show arp
SW#traceroute mac xxxx.xxxx.xxxx dest.macx.addr
SW#traceroute mac ip 192.168.32.1 192.168.32.200
SW#show mac address-table dynamic
SW#show mac address-table int Gi1/0/13
SW#show arp | i 192.168.32.200

 

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